Nerve cuff electrode locking mechanism

ABSTRACT

A lead comprising a lead body, a lead connector terminal affixed to a proximal end of the lead body, and a cuff body affixed to a distal end of the lead body, an electrode contact affixed to the cuff body, and an electrical conductor between the connector terminal and electrode contact. The lead further comprises a strap extending from a first region of the cuff body, a buckle disposed on a second region of the cuff body, and a locking feature, e.g., protuberance, ring, or wrinkle, associated with the strap. The locking feature is configured for being pulled through the buckle to dispose the cuff body around a nerve in response to a tensile force applied to the strap. The locking feature is configured for abutting an edge of the buckle in response to a release of the tensile force to secure the cuff body around the nerve.

RELATED APPLICATION DATA

The present application is a continuation of U.S. patent application Ser. No. 15/967,332, filed Apr. 30, 2018, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/500,080, filed May 2, 2017, and U.S. Provisional Patent Application Ser. No. 62/500,091, filed May 2, 2017, which are expressly incorporated herein by reference. This application is also related to U.S. patent application Ser. No. 15/967,468, filed on Apr. 30, 2018, which is expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to implantable neurostimulation leads, and specifically relates to implantable nerve cuff electrodes that can be used to stimulate nerves to treat ailments, such as obstructive sleep apnea (OSA).

BACKGROUND OF THE INVENTION

Obstructive sleep apnea (OSA) is a common disorder in which the upper airway of a patient can become obstructed (apnea) or partially obstructed (hypopnea) during sleep. It is highly prevalent, affecting 5%-10% of the adult population in the United States, and has serious effects and comorbidities, such as daytime sleepiness, snoring, poor sleep quality, and an increased risk of cardiovascular disease and motor vehicle accidents. Conventional treatments of OSA include using continuous positive airway pressure (CPAP) techniques or performing upper airway surgery. However, due to discomfort, CPAP has a low adherence rate over time, thereby limiting its effectiveness. Alternatively, upper airway surgery is painful and requires a prolonged recovery period, and therefore is used as a last resort to the treatment of OSA, reserved for only extreme cases.

In response to disadvantages of the conventional techniques for treating OSA, a new approach involves stimulating the hypoglossal nerve or its branches, which innervates the upper airway muscle, to increase the patency of the upper airway of the patient, thereby preventing or minimizing the onset of OSA. For example, one such neurostimulation system for treating OSA includes a neurostimulator device that stimulates one or more branches of the hypoglossal nerve via electrodes that are implanted at the hypoglossal nerve. Further details discussing such a neurostimulation system are described in U.S. Patent Publication No. 2016/0354608, which is expressly incorporated herein by reference.

It is desirable that any electrode implanted in contact with a nerve, such as the hypoglossal nerve, continually remain in firm contact with such nerve to maximize the effectiveness of the stimulation regimen. However, certain regions of the patient, such as the neck region, are subject to various dynamic forces that may dislodge or otherwise cause an electrode to migrate from or otherwise temporarily move from its original or desired implantation site, which may have deleterious effect on the stimulation regimen, and thus, the treatment of the ailment, such as OSA.

A reliable solution to this migration problem is to use a nerve cuff electrode device, which can be circumferentially placed around the nerve to deliver effective electrical stimulation to that nerve. This approach provides a more effective anchoring means that keeps the electrode in firm contact with the nerve to which it is attached even when the implantation site is subject to dynamic forces. For treating OSA, a nerve cuff can be wrapped around the hypoglossal nerve trunk or its branch that innervates the muscle that protrudes the tongue.

A conventional approach to securing a nerve cuff electrode to a nerve involves placing the cuff, which is generally C-shaped, around the nerve and tightly closing and sealing the cuff by tying sutures at two edges or flaps of the cuff to fully encircle the nerve. However, using sutures to secure the nerve cuff electrode has several disadvantages. For example, braided suture material easily attracts and retains contaminants, connective tissue can grow on the sutures making removal of the cuff difficult, and sutures tend to breakdown when exposed to a fluid environment, thereby resulting in failure of the sutures and potentially allowing the cuff to open.

There, thus, remains a need for securing a nerve cuff electrode to a nerve.

SUMMARY OF THE INVENTION

In accordance with present invention, an electrode lead comprises an elongated lead body, at least one lead connector terminal affixed to the proximal end of the lead body, and a biologically compatible, elastic, electrically insulative cuff body affixed to the distal end of the lead body, and at least one electrical conductor extending through the lead body between the connector terminal(s) and the electrode contact(s). The cuff body is configured for being circumferentially disposed around a nerve, and has opposing first and second regions. The cuff body may be composed of, e.g., silicone. The cuff body may be configured and sized for being placed around on a human hypoglossal nerve trunk or its branch nerve. The cuff body may be configured for expanding and accommodating both a normal-sized nerve diameter and then later, after implantation of the electrode lead, an increased nerve diameter due to swelling, thereby preventing nerve constriction due to the nerve swelling. In one embodiment, the electrode contact(s) is configured for being on an inner surface of the cuff body when secured around the nerve. The electrode lead further comprises a strap extending from the first region of the cuff body, and a buckle disposed on the second region of the cuff body. The strap may have, e.g., a thickness less than 1 mm.

In accordance with a first aspect of the present invention, the electrode lead comprises at least one raised protuberance (e.g., a button or a dome) disposed on a planar surface of the strap. The strap with the raised protuberance(s) is configured for being pulled through an aperture of the buckle to dispose the cuff body around the nerve in response to a tensile force applied to the strap, and one of the raised protuberance(s) is configured for abutting an edge of the buckle in response to a release of the tensile force to secure the cuff body around the nerve. In another embodiment, the one raised protuberance and the strap, in their relaxed state, have a combined first height, and the aperture of the buckle, in its relaxed state, has a second height less than the first height. In still another embodiment, the first height is less than twice the second height.

In accordance with a second aspect of the present invention, the electrode lead comprises a ring incorporated into the strap. The strap with the ring is configured for being pulled through an aperture of the buckle to dispose the cuff body around the nerve in response to a tensile force applied to the strap, and the ring is configured for abutting an edge of the buckle in response to a release of the tensile force to secure the cuff body around the nerve. In one embodiment, the ring, in its relaxed state, has a first width, and the aperture of the buckle, in its relaxed state, has a second width less than the first width. In still another embodiment, the first width is less than twice the second width. The ring, in its relaxed state may be, e.g., circular, oval, or rectangular.

In accordance with a third aspect of the present invention, the electrode lead comprises at least one wrinkle (e.g., a folded region or a curved region) incorporated into the strap. The strap with the wrinkle(s) is configured for being pulled through an aperture of the buckle to dispose the cuff body around the nerve in response to a tensile force applied to the strap, and one of the wrinkle(s) is configured for abutting an edge of the buckle in response to a release of the tensile force to secure the tightened cuff body around the nerve. In one embodiment, the one wrinkle, in its relaxed state, spans a first height, and the aperture of the buckle, in its relaxed state, has a second height less than the first height. In still another embodiment, the first height is less than twice the second height.

Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of preferred embodiments of the present invention, in which similar elements are referred to by common reference numerals. In order to better appreciate how the above-recited and other advantages and objects of the present inventions are obtained, a more particular description of the present inventions briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a perspective view of an electrode lead constructed in accordance with one embodiment of the present inventions;

FIG. 2 is a plan view of a cuff electrode of the electrode lead of FIG. 1, which can be rolled up and circumferentially disposed around a nerve;

FIG. 3 is an end view of the cuff electrode of FIG. 2;

FIG. 4 is a perspective view of the cuff electrode of FIG. 2, particularly showing a protuberance used in a strap and buckle arrangement for securing the cuff electrode to the nerve;

FIG. 5a is a side view of one embodiment of the protuberance of FIG. 4 in the form of a button;

FIG. 5b is a side view of another embodiment of the protuberance of FIG. 4 in the form of a dome;

FIGS. 6a and 6b are respective top and side views illustrating the protuberance prior to pulling the strap through the buckle;

FIGS. 7a and 7b are respective top and side views illustrating the protuberance pulled into the buckle by pulling the strap;

FIGS. 8a and 8b are respective top and side views illustrating the protuberance pulled out of the buckle by pulling the strap;

FIGS. 9a and 9b are respective top and side views illustrating the protuberance engaging the edge of the buckle in a locked position by releasing tension on the strap;

FIG. 10 is a perspective view of the cuff electrode of FIG. 2, particularly showing a ring used in a strap and buckle arrangement for securing the cuff electrode to the nerve;

FIG. 11a is a top view of one embodiment of the ring of FIG. 10 in the form of a circular ring;

FIG. 11b is a top view of another embodiment of the ring of FIG. 10 in the form of an oval ring;

FIG. 11c is a top view of still another embodiment of the ring of FIG. 10 in the form of a rectangular ring;

FIGS. 12a and 12b are respective top and side views illustrating the ring prior to pulling the strap through the buckle;

FIGS. 13a and 13b are respective top and side views illustrating the ring pulled into the buckle by pulling the strap;

FIGS. 14a and 14b are respective top and side views illustrating the ring pulled out of the buckle by pulling the strap;

FIGS. 15a and 15b are respective top and side views illustrating the ring engaging the edge of the buckle in a locked position by releasing tension on the strap;

FIG. 16 is a perspective view of the cuff electrode of FIG. 2, particularly showing a wrinkle used in a strap and buckle arrangement for securing the cuff electrode to the nerve;

FIG. 17a is a side view of one embodiment of the wrinkle of FIG. 16 in the form of a folded region;

FIG. 17b is a side view of another embodiment of the wrinkle of FIG. 16 in the form of a curved region;

FIGS. 18a and 18b are respective top and side views illustrating the wrinkle prior to pulling the strap through the buckle;

FIGS. 19a and 19b are respective top and side views illustrating the wrinkle pulled into the buckle by pulling the strap;

FIGS. 20a and 20b are respective top and side views illustrating the wrinkle pulled out of the buckle by pulling the strap; and

FIGS. 21a and 21b are respective top and side views illustrating the wrinkle engaging the edge of the buckle in a locked position by releasing tension on the strap.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIGS. 1-3, an electrode lead 10 constructed in accordance with one embodiment of the present invention will now be described. Although the electrode lead 10 lends itself well to be used in the treatment of OSA by stimulating the hypoglossal nerve, the electrode lead 10 may be used for any medical treatment where it is desired to stimulate a nerve.

The electrode lead 10 generally comprises an elongated lead body 12 having a proximal end 14 and a distal end 16, at least one lead connector terminal 18 (two shown) affixed to the proximal end 14 of the lead body 12, a cuff body 20 affixed to the distal end 16 of the lead body 12, at least one electrode contact 22 (three shown in FIG. 2) disposed on the cuff body 20, and at least one electrical conductor 24 (two shown) extending through the lead body between the lead connector terminals 18 and the electrode contacts 22. As shown, the cuff body 20 can be circumferentially disposed around tissue, e.g., a nerve 26, such that the electrode contacts 22 are disposed on an inner surface of the cuff body 20 in contact with the nerve 26.

In the illustrated embodiment shown in FIGS. 2 and 3, the electrode contacts 22 may be used to form a guarded tripolar electrode arrangement (e.g., anode-cathode-anode) for purposes of stimulating the nerve 26. Two of the electrode contacts 22 (the anodes) are ganged together and coupled to one of the lead connector terminals 18 via an electrical conductor 24, and the remaining electrode contact 22 (the cathode) is coupled to the other lead connector terminal 18 via the other electrical conductor 24. It should be appreciated that, alternatively, the number of electrode contacts 22, lead connector terminals 18, and electrical conductors 24 can be identical, such that electrode contacts 22 may be energized independently of each other.

To this end, the lead connector terminals 18 of the proximal end 14 of the lead body 12 can be inserted into a connector block 30 of a neurostimulation device 28, which supplies electrical pulses to one or more of the electrode contacts 22 in accordance with a stimulation regimen. Recording electrodes (not shown) can also be connected to the neurostimulation device 28 to provide sensed physiological signals to the neurostimulation device 28. In an alternative embodiment, one or more of the electrode contacts 22 of the electrode lead 10 can serve as a recording electrode.

The lead body 12 and cuff body 20 may be composed of an elastic, electrically insulative, biocompatible, material, such as, e.g., medical-grade silicone, polyurethane, etc. The lead connector terminals 18 may be composed of a suitable electrically conductive material, such as, e.g., stainless steel, and the electrode contacts 22 may be composed of a suitable electrically conductive and biocompatible material, such as gold, or 90/10 or 80/20 Platinum-Iridium alloy. The electrical conductors 24 may likewise be composed of a suitable electrically conductive and biocompatible material, such as MP35N, MP35N with silver core, stainless steel, or tantalum. The cuff body 20 is relatively thin, e.g., and may have a thickness less than 1 mm, and may often be less than 0.5 mm, so that the cuff body 20 may be easily disposed around in conformance with the nerve 26. The cuff body 20 may take the form of a planar sheet (as best shown in FIG. 2) that can be rolled up on itself to be circumferentially disposed around the nerve 26 (as best shown in FIG. 1).

The electrode lead 10 includes locking features that allow the cuff body 20 to be secured around the nerve 26 without the use of sutures and in a manner that minimizes the chance that the cuff body 20 can be dislodged from the nerve 26 after implantation of the cuff around the nerve.

In particular, the cuff body 20 may comprise a strap 32 extending from a first region 36 of the cuff body 20, and a buckle 34 disposed on the surface of a second region 38 of the cuff body 20. In the illustrated embodiment, the strap 32 and cuff body 20 are unitary in nature and may be formed of the same planar material, such that the strap 32 is a narrower extension of the cuff body 20. Thus, in the embodiment shown, the strap 32 and cuff body 20 have the same thickness. In the illustrated embodiment, the strap 32 takes the form of a tongue that is suitably connected to the planar surface of the first region 36 of the cuff body 20. The buckle 34 comprises an aperture 40 (as best shown in FIG. 3) through which the strap 32 can be inserted to allow the cuff body 20 to be conveniently secured around the nerve 26. The width w of the strap 32 is preferably slightly less or equal to the width of the aperture 40 of the buckle 34 before the strap 32 is inserted through the aperture 40 of the buckle 34. As best shown in FIG. 1, the strap 32 may be pulled through the aperture 40 (shown in FIG. 3) of the buckle 34. The buckle 34, aperture 40, and strap 32 are sized in a manner, such that when the strap 32 is pulled through the aperture 40, the outer surface of the strap 32 firmly engages the inner surface of the buckle 34.

The electrode lead 10 further comprises a locking feature closely associated with the strap 32 for interacting with the buckle 34 in a manner that prevents the strap 32 from being pulled back through the buckle 34.

In one embodiment of a cuff body 20 a illustrated in FIGS. 4-9, the locking feature takes the form of at least one raised protuberance 42 a (only a single protuberance 42 a is illustrated) disposed on the planar surface of the strap 32. The protuberance 42 a may be, e.g., a button 42 a-1 (FIG. 5a ) or a dome 42 a-2 (FIG. 5b ). The protuberance 42 a is positioned on the strap 32, such that the strap 32, with the protuberance 42 a, will pass all the way through the aperture 40 of the buckle 34 when the cuff body 20 a is placed around the nerve 26.

Although the protuberance 42 a may hinder the insertion of the strap 32 through the aperture 40 of the buckle 34 (as shown in FIGS. 6a and 6b ), due to the elastomeric nature of the buckle 34 and the protuberance 42 a, the protuberance 42 a can be pulled within the aperture 40 of the buckle 34 (as shown in FIGS. 7a and 7b ), and then out through the aperture 40 of the buckle 34 (as shown in FIGS. 8a and 8b ) in response to the application of a substantial amount of tensile force to end of the strap 32 in the direction 46, e.g., by using a surgical tool, such as tweezers. When the tensile force is released from the strap 32, the spring force built up in the strap 32 by the previous application of the tensile force in the direction 46 causes the protuberance 42 a to retract back towards the buckle 34 in the direction 48, causing the protuberance 42 a to abut the edge 44 of the buckle 34, thereby securing and locking the cuff body 20 a around the nerve 26 (as shown in FIGS. 9a and 9b ).

The combined height h1 (FIG. 6b ) of the protuberance 42 a and strap 32 is preferably selected, such that the buckle 34 can stretch and expand enough to accommodate its passage through the aperture 40 of the buckle when a substantial tensile force is applied to the strap 32 using a surgical tool, while ensuring that the buckle 34 cannot distort enough to overcome the abutment force between the protuberance 42 a and the edge 44 of the buckle 34 after implantation of the cuff body 20 a around the nerve 26. In the illustrated embodiment shown in FIG. 6b , the combined height h1 of the protuberance 42 a and strap 32, in their relaxed state, is greater than the height h2 of the aperture 40 of the buckle 34, in its relaxed state, but less than twice the height h2 of the aperture 40 of the buckle 34, in its relaxed state.

Referring now to FIGS. 10-15, another embodiment of a cuff body 20 b is the same as the cuff body 20 a described above, but instead of a protuberance, the locking feature takes the form of a ring 42 b incorporated into the strap 32. In the illustrated embodiment, the ring 42 b, in its relaxed state, may be a circular ring 42 b(1) (FIG. 11a ), although in other embodiments, the ring 42 b, in its relaxed state, may be an oval ring 42 b(2) (FIG. 11b ) or even a rectangular ring 42 b(3) (FIG. 11c ).

The ring 42 b is positioned on the strap 32, such that the strap 32, along with the ring 42 b, will pass all the way through the aperture 40 of the buckle 34 when the cuff body 20 b is placed around the nerve 26. Although the ring 42 b, in its relaxed state, may hinder the insertion of the strap 32 through the aperture 40 of the buckle 34 (as shown in FIGS. 12a and 12b ), due to the elastomeric nature of the ring 42 b, the ring 42 b collapses inward and can be pulled within the aperture 40 of the buckle 34, which may expand to accommodate the collapsed ring 42 b (as shown in FIGS. 13a and 13b ). The collapsed ring 42 b may then be passed through the aperture 40 of the buckle 34 (as shown in FIGS. 14a and 14b ) in response to the application of a substantial amount of tensile force to the end of the strap 32 in the direction 46, e.g., by using a surgical tool, such as tweezers. When the tensile force is released from the strap 32, the spring force built up in the strap 32 by the previous application of the tensile force in the direction 46 causes the ring 42 b to expand outward to its relaxed state and retract back towards the buckle 34 in the direction 48, causing it to abut the edge 44 of the buckle 34, thereby securing and locking the cuff body 20 b around the nerve 26 (as shown in FIGS. 15a and 15b ).

The width w1 of the ring 42 b, in its relaxed state, is preferably selected, such that the ring 42 b can collapse inwardly enough to pass through the aperture 40 of the buckle 34 when a tensile force is applied to the strap 32 using a surgical tool. In the illustrated embodiment shown in FIG. 12a , the width w1 of the ring 42 b, in its relaxed state, is greater than the width w2 of the aperture 40 of the buckle 34, in its relaxed state, but less than twice the width w2 of the aperture 40 of the buckle 34, in its relaxed state.

Referring now to FIGS. 16-21, still another embodiment of a cuff body 20 c is the same as the cuff body 20 b described above, but instead of a ring, the locking feature takes the form of a wrinkle 42 c incorporated into the strap 32. In the illustrated embodiment, the wrinkle 42 c, in its relaxed state, may be a folded region 42 c-1 (FIG. 17 a), although in other embodiments, the wrinkle 42 c, in its relaxed state, may be a curved region 42 c-2 (FIG. 17b ).

The wrinkle 42 c is positioned along the length of strap 32, such that the strap 32, along with the wrinkle 42 c, will pass all the way through the aperture 40 of the buckle 34 when the cuff body 20 c is placed around the nerve 26. Although the wrinkle 42 c, in its relaxed state, may hinder the insertion of the strap 32 through the aperture 40 of the buckle 34 (as shown in FIGS. 18a and 18b ), due to the elastomeric nature of the wrinkle 42 c, the wrinkle 42 c straightens and can be pulled within the aperture 40 of the buckle 34 (as shown in FIGS. 19a and 19b ), and then out through the aperture 40 of the buckle 34 (as shown in FIGS. 20a and 20b ) in response to the application of a substantial amount of tensile force to the strap 32 in the direction 46, e.g., by using a surgical tool, such as tweezers. When the tensile force is released from the strap 32, the spring force built up in the strap 32 by the previous application of the tensile force in the direction 46 causes the wrinkle 42 c to bend back to its relaxed state and retract back towards the buckle 34 in the direction 48, causing it to abut the edge 44 of the buckle 34, thereby securing and locking the cuff body 20 c around the nerve 26 (as shown in FIGS. 21a and 21b ).

The span of the height h1 of the wrinkle 42 c, in its relaxed state, is preferably selected, such that the wrinkle 42 c can straighten enough to pass through the aperture 40 of the buckle when a tensile force is applied to the strap 32 using a surgical tool, while ensuring that the buckle 34 cannot collapse inwardly enough to overcome the abutment force between the wrinkle 42 c and the edge 44 of the buckle 34 in response to tensile forces applied to the strap 32 by the swelling of the nerve 26. In the illustrated embodiment, the wrinkle 42 c, in its relaxed state, spans a height h1 that is greater than the height h2 of the aperture 40 of the buckle 34, in its relaxed state, but less than twice the height h2 of the aperture 40 of the buckle 34, in its relaxed state.

In optional embodiments, self-expanding features can be incorporated into the cuff body 20 (e.g., cuff bodies 20 a, 20 b, or 20 c) to expand and accommodate both a normal-sized nerve diameter and then later, after implantation of the electrode lead 10, an increased nerve diameter due to swelling, thereby preventing nerve constriction due to the nerve swelling, as described in U.S. patent application Ser. No. ______, entitled “Self-Adjusting Features in a Cuff Electrode,” which is expressly incorporated herein by reference.

Although particular embodiments of the present inventions have been shown and described, it will be understood that it is not intended to limit the present inventions to the preferred embodiments, and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present inventions. Thus, the present inventions are intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the present inventions as defined by the claims. 

What is claimed is:
 1. An electrode lead, comprising: an elongated lead body having a proximal end and a distal end; at least one lead connector terminal affixed to the proximal end of the lead body; a biologically compatible, elastic, electrically insulative cuff body affixed to the distal end of the lead body, the cuff body configured for being circumferentially disposed around a nerve, the cuff body having opposing first and second regions; at least one electrode contact affixed to the cuff body; at least one electrical conductor extending through the lead body between the at least one lead connector terminal and the at least one electrode contact; a strap extending from the first region of the cuff body; a buckle disposed on the second region of the cuff body; and at least one raised protuberance disposed on a planar surface of the strap; wherein the strap with the at least one raised protuberance is configured for being pulled through an aperture of the buckle to dispose the cuff body around the nerve in response to a tensile force applied to the strap; and wherein one of the at least one raised protuberance is configured for abutting an edge of the buckle in response to a release of the tensile force to secure the cuff body around the nerve. 